Polymers with a comb structure of pendant side chains are a new class of organic materials which exhibit interesting optical properties.
Comb-like liquid crystalline polymers are described in Eur. Polym J., 18, 651 (1982); Advanced Polymer Science, Liquid Crystal Polymers II/III, Springer-Verlag, New York (1984), pages 215-220; and in U.S. Pat. Nos. 4,293,435 and 4,631,328. The disclosed polymeric structures have been developed for their mesogenic optical properties which have prospective utility in opto-electronic display devices.
In U.S. Pat. Nos. 4,694,066; 4,755,574; and 4,762,912 liquid crystalline polymers are described which have pendant side chains which exhibit nonlinear optical susceptibility, in addition to mesogenic properties. U.S. Pat. No. 4,792,208 discloses nonlinear optically responsive organic compounds and side chain polymers in which the molecular dipoles have an electron donor moiety linked through a conjugated bonding system to an electron acceptor sulfonyl moiety. Japanese patent application 88175834 discloses acrylate polymers and copolymers which have nitro(ethylhydroxyethylamino)azobenzene side chains. J. Org. Chem., 53, 5538 (1988) describes the synthesis and reactions of cyanovinyl-substituted benzenediazonium salts, and the production of acrylate copolymers with azostilbene dye side chains.
Nonlinear optical properties of organic and polymeric materials was the subject of a symposium sponsored by the ACS division of Polymer Chemistry at the 18th meeting of the American Chemical Society, September 1982. Papers presented at the meeting are published in ACS Symposium Series 233, American Chemical Society, Washington, D.C. 1983.
Thin films of organic or polymeric materials with large second order nonlinearities in combination with silicon-based electronic circuitry have potential as systems for laser modulation and deflection, information control in optical circuitry, and the like.
Other novel processes occurring through third order nonlinearity such as degenerate four-wave mixing, whereby real-time processing of optical fields occurs, have potential utility in such diverse fields as optical communications and integrated circuit fabrication.
Liquid crystalline side chain polymers which exhibit nonlinear optical properties are suitable for application as a nonlinear optical component in optical light switch and light modulator devices. One disadvantage of a liquid crystalline side chain polymer optical medium is a loss of transmission efficiency due to light scattering by deviations from ideal mesogenic order.
There is continuing interest in the theory and practice of optically-responsive polymers which are characterized by an oriented state of comb-like side chain structures.
There is also an increasing research effort to develop new nonlinear optical organic systems for prospective novel phenomena and devices adapted for laser frequency conversion, information control in optical circuitry, light valves and optical switches. The potential utility of organic materials with large second order and third order nonlinearities for very high frequency application contrasts with the bandwidth limitations of conventional inorganic electrooptic materials.
Accordingly, it is an object of this invention to provide novel optically responsive monomers and polymers.
It is another object of this invention to provide acrylic copolymers having side chains which exhibit nonlinear optical response.
It is a further object of this invention to provide optical light switch and light modulator devices with a transparent polymeric nonlinear optical component comprising a thin film of an acrylic copolymer with nonlinear optically-responsive pendant side chains which can be uniaxially oriented by an external field.
Other objects and advantages of the present invention shall become apparent from the accompanying description and examples.